Decorated thermoplastics and process of making same



- Feb. 28, 1933. J. F. wALsH ET AL 1,899,068

DECORATED THERMOPLASTIGS AND PROCESS OF MAKING SAME Filed Jan. 11 1930was 93/3521? 6 9 3 gm! A'lvnensev 9% bum.

ATTORN EY5 Patented Feb. 28, 1933 UNITED STATES PATENT OFFICE JAMES F.WALSH, OF SOUTH ORANGE, AND BJORN ANDERSEN, OF NEWARK, NEW

JERSEY, ASSIGNORS TO CELLULOID CORPORATION, A CORPORATION OF NEW JERSEYDECORATED THERMOPLASTICS AND PROCESS OF MAKING SAME Application filedJanuary 11, 1930. Serial No. 420,159.

This invention pertains to the general class,

of decorated materials and particularly to the class of decoratedthermoplastics.

The invention is particularly applicable to the decoration of cellulosicthermoplastics which are used so extensively for all forms ofornamentation. The present practice of ornamenting thermoplastics withmetallic substances is largely confined to the use of metal foil,together with a die or stamp to impress portions of the foil into thematerial. The operations are more or less cumbersome, the percentage ofrejects fairly high, and the amount of waste metallic foil resultingfrom the operation is tremendous. This operation therefore, is limitedto the use of metallic V foils of relatively low cost.

An object of our invention, therefore is to provide novel means fordecorating thermoplastics with metals.

A further object of our invention is to provide novel means fordecorating thermoplastics with metallic substances wherein thedecorating may be expeditiously performed, wherein rejects are reducedto a minimum, wherein a superior bond is effected between thethermoplastic and the metallic substance, wherein the amount of wastemetallic substance is reduced to a minimum, and that is otherwise highlysatisfactory for its intended purpose.

Many other objects and advantages will become apparent to personsskilled in the art as the specification proceeds.

Our novel invention comprises applying metallic substances in the formof a fused spray to roughened portions of the thermoplastic. Thetemperature of the fused metallic spray is suflicient to cause the metalto firmly bind itself to the roughened portions of the thermoplastic.Further application of the metallic spray serves to build up thethickness of the applied metal, each layer of spray binding itselffirmly and becoming a part of the layer previously deposited. It istherefore merely necessary to reproduce the desired design on thesurface of the thermoplastic by roughening the surface thereof, leavingthe balance of the surface polished or ,have been roughened. This is nodoubt due to an interlocking of the particles assisted by fusion ofexposed parts of the thermoplastic. The sprayed metal is easilyremovable from all polished parts. Should the metal which is applied tothe roughened portions overlap the polished portions, the overlappingedges may be readily trimmed away. It is of course, understood that astencil or similar device may be used if desired.

In applying the metallic spray to the thermoplastic, we prefer to startwith metals or alloys having low melting points such as zinc tin,pewter, etc. After the thermoplastic is given a thin coating of a lowmelting point metal, we prefer to apply a metal having a high meltingpoint, such as brass, copper, bronze, silver, gold, platinum, or alloysof same. Although the metals of higher melting point may be applieddirectly to the thermoplastic, we find that a superior bond is effectedby using a metal having a low melting point before using the metal oralloy having a high melting point. It is understood, however, that theentire decoration may be carried out in any of the metals or alloys oflow melting point if desired.

The final metallic surface may be finished by any of the known meansapplicable to the particular metal or, alloy used, such as polishing,grinding, applying a mat, satin or other finish, etc.

The preferred thermoplastic materials are those made with cellulosenitrate and/or cellulose acetate, and particularly those made withcellulose acetate. Examples of other thermoplastic materials are thosemade with cellulose esters such as cellulose formate,

cellulose propionate, and cellulose butyrate, as well'as those made withmethyl cellulose, ethyl cellulose, benzyl cellulose, cellulosephthalate,viscose, casein, etc.

In the drawing wherein like reference characters are appended to likeparts in the various figures,

Figure 1 is a'plan View of a mirror back having a design reproducedthereon by roughening the surface.

Figure 2 is a plan view of the mirror back shown in Figure 1 but havinga metallic coating applied to the roughened portions.

Figure 3 is a section on line 3-3 of Figure 2.

Figure 4 is a section similar to Figure 3 but showing a modification.

Figure 5 is a section illustrating a method of forming a plurality ofparallel lines of different metals.

Figure 6 is a section similar to Figure 5 illustrating a roughenedportion filled out with a plurality of parallel lines of differentmetals.

Referring to Figures 1. 2, and 3, wherein a mirror 15 is shown merelyfor the purposes of illustration, the border 1 and the design 2 alsoshown merely for the purposes of illustration, have been reproduced onthe mirror back by roughening the surface thereof. This roughening maybe carried out by any means such as with a tool, with emery cloth, sandpaper, or other abrasive with a blast of abrasive, such as a sand blast,etc., or by any other means known in the art. The surface may be merelyroughened or a roughened channel may be formed such as illustrated, moreor less in exaggerated scale in Figure 3.

At 3 and 4, in Figure 2, are shown the border 1 and design 2,respectively covered with a metal. The metallic portions may be of anythickness and need not be flush with the surface of the mirror unlessdesired, but may be sunken or elevated.

In Figure 4. the metallic portions 5 are of one metal and the metallicportions 6 are of a second metal. As previously pointed out, it is oftendesirable to begin coating with one metal and to finish the coating witha second metal.

In Figure 5 is illustrated means for forming adjacent portions withdifferent metals such for instance, as silver, and gold. The roughenedportion 7 comprises two parts, 8 and 9. The part 8 is first formed andfilled lwith metal 10. The part 9 is then formed along side of thesolidified metal 10 and is then filled with the metal 11. Any number ofdifferent metals and designs may be used by this or equivalent means,and any desired contrast between metals may be formed.

It is, of course, understood that the term metals as used herein, alsoincludes alloys. The apparatus for applying the metallic spray may be ofany desired design and operation. In other Words, any means known in theart to produce the metallic spray may be employed. WV e havesuccessfully employed apparatus for this purpose which comprises feedinga metallic rod end-wise into an oxyacetylene flame and blowing the fusedmetal by suitable means against the roughened portions of the plastic.

Having described our invention, it is obvious that many modificationsmay be made in the same within the scope of the claims without departingfrom the spirit of the invention.

We claim:

1. The process of decorating a polished thermoplastic surface comprisingroughening selected portions thereof, applying a fused metallic spray tosaid surface and then removing the metal from the polished portionsthereof.

2. The process of decorating a polished surface of a cellulose acetateplastic comprising roughening selected portions thereof, applying afused metallic spray to said surface and then removing the metal fromthe polished portions thereof.

In testimony whereof, we have hereunto subscribed our names:

JAMES F. WALSH.

BJORN ANDERSEN.

